/Engine/Source/Runtime/MediaAssets/Public/Misc/MediaBlueprintFunctionLibrary.h
To filter for a specific subset of devices, use the MakeBitmask node with EMediaWebcamCaptureDeviceFilter as the Bitmask Enum.
static void EnumerateWebcamCaptureDevices ( [TArray](API\Runtime\Core\Containers\TArray)< [FMediaCaptureDevice](API\Runtime\MediaAssets\Misc\FMediaCaptureDevice) > & OutDevices, int32 Filter )